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1. Field of the Invention
This invention relates to a system for providing an advanced warning to motor vehicles of the presence or approach of railroad trains and emergency vehicles.
2. General Background of the Invention
The more immediate application of the present invention is to prevent vehicular accidents with trains at railroad crossings. Improvements in newer models of automobiles have sound-proofed interior compartments which all but eliminated outside noise making interior of the vehicles soundproof and operators are isolated from outside disturbances, such as the clang of a bell at a railroad grade crossing. Further, with the improvement of sound systems in automobiles and the addition of such as cellular telephones and VCRs for viewing by children, the driver""s attention is easily obscured and/or distracted from activity in the roadway.
A number of inventions have been developed which are directed to the problems stated above, however none have exhibited sufficient effectiveness, capacity or flexibility to become a significant commercial factor in the market. Systems developed to date fall roughly into two categories: 1) those wherein a radio frequency transmitter is located in the cab of the engine or emergency vehicle and transmits on a designated frequency to a receiver in the vehicle such various information as speed and proximity; and 2) GPS systems wherein information on the locomotive or emergency vehicle is transmitted to the satelite and relayed to a receiver in the automobile.
Examples of the state of the art systems are found in the following patents:
U.S. Pat. No. 1,978,286 to Sommer where the audio receiver equipment located on the train to detect, as by a microphone, ambient audio information such as whistles, warning bells and train sounds such as the general rumble of the train wherein such audio sounds are transmitted to a receiver on the automobile, which broadcasts such sounds in the passenger compartment when the vehicle receiver is within range of the transmitter.
U.S. Pat. No. 3,233,217 to Bost illustrates a system wherein emergency signals such as sirens, bells and whistles are received by microphone in a transmitter located in a train or emergency vehicle and coded according to which type of signal is received and then transmitted at a limited range for receipt by a receiver equipped automobile, which signals within the automobile which of the various alarm signals has been received. In the preferred embodiment a visual indicator is placed on the dashboard or other prominent place for observation by the driver.
U.S. Pat. No. 3,532,986 to Belushia, et al, illustrates a system similar to the above however including the capacity for the automobile to transmit an alarm signal back to the approaching emergency vehicle or train alerting the driver or engineer to traffic in the area.
U.S. Pat. No. 3,735,342 to Helliker, et al, illustrates a transmitter-receiver system which is sensitive to the particular frequencies of sirens (600 Hz, 900 Hz and 1200 Hz) to transmit an alarm to an in-range automobile of the approach of an emergency vehicle.
U.S. Pat. No. 3,760,349 to Keister, et al, discloses an emergency warning system which operates on 500 Hz and 1000 Hz frequencies to detect sirens and transmits an alarm to a receiver in range when the frequencies are detected.
U.S. Pat. No. 4,942,395 to Ferrari, et al, illustrates a system in which a transmitter located in a locomotive transmits a distance limited, coded signal to a receiver mounted a railroad grade crossing, which in turn transmits a shortwave radio signal to a receiver-equipped automobile. Information is transmitted from the locomotive so long as the locomotive is in motion.
U.S. Pat. No. 5,235,329 to Jackson discloses a transmitter-receiver combination wherein the transmitter operates in the citizens band frequency such that a siren detected by the transmitter unit initiates an alarm transmitted on the citizens band frequency for receivers within the limited range of the transmitter.
U.S. Pat. No. 5,729,213 to Ferrari, et al, illustrates a radio-transmitter combination, operation of which is initiated and terminated by the action of an in-track pressure or magnetic sensor which determines the approach and the departure of a train to and from a railway grade crossing. The actual transmitter and receiver information may be broadcast from a battery or hardwired transmitter placed on the crossing indicator standard for proximity related transmission and reception from approaching vehicles and trains.
U.S. Pat. No. 6,025,789 to Lane, et al, discloses a radio transmitter-receiver combination which operates in conjunction with the FSK system currently employed in trains as xe2x80x9chead of trainxe2x80x9d and xe2x80x9ctail of trainxe2x80x9d devices. Such systems typically code a variety of train related information such as brake pressure and speed of the train. The illustrated system utilizes the FSK train specific information to confirm that the transmitted information is from the head end of the train and that it is on the train specific frequency, thereby eliminating the possibility of false signals. The system is also equipped with a whistle detector to provide an additional in-range alarm signal on the event of the blowing of the whistle.
The second category of train or emergency vehicle warning systems operate in conjunction with ground position system receivers. U.S. Pat. No. 5,554,982 to Shirkey, et al, discloses a GPS based system in which a locomotive based or track position based system transmits train speed and position information to the GPS system, which receives the information and calculates emergency zones in relation to railroad grade crossings. A companion vehicle based receiver receives the GPS train information and using the vehicle speed and position information, calculates whether the vehicle will enter the emergency zone, and if so, emits an alarm.
U.S. Pat. No. 5,620,155 to Michaelek illustrates a GPS based system centralized in a locomotive which is capable of identifying railroad grade crossings being approached by the locomotive for the purpose of the locomotive based system to actuate the grade crossing alarm as well as perform maintenance checks on the various components such as status of lights, arm actuation, and sound alarms. The system also includes a related receiver in a vehicle such that those vehicles in proximity to the identified grade crossing also received a warning signal.
U.S. Pat. Nos. 5,699,986 and 5,890,682 to Welk illustrate a GPS based collision avoidance system which is centralized to specific grade crossings, such that the unit receives and process such as speed and position information of comparable transmitter-receiver systems on trains and vehicles to generate a variety of alarm level warnings, depending upon the proximity of train or vehicle, including alerting the vehicle of the proximity of a grade crossing and the possibility of a collision.
The present invention bears resemblance to the above described prior art systems only in the aspect that information is received by an approaching automobile of the concurrent approach of a train to a grade crossing or an emergency vehicle in the immediate area. The apparatus and methodology of the inventive system provide a significantly improved overall reliability of reporting as well as utilizing existing components already incorporated into railway grade crossing signals and gates. Accordingly, the present invention provides a railway warning system which may be standardized to equipment already mandated by various state and federal regulatory codes.
It is an object of the present invention to provide method and apparatus for the transmission of a warning of a vehicle approaching a railroad grade crossing to alert its occupants, including particularly the driver, of any approach of a train to that grade crossing. The present invention operates integrally with a railroad grade crossing warning system, utilizing certain of the event information collected and recorded within the crossing analyzer of the grade crossing warning system to supply such information to the vehicle, which may then trigger various alarms and information sources in the receiver equipment within the vehicle. The transmitter, operating in response to preselected information supplied to the crossing analyzer, preferably encodes such information as the approach of a train to the specific grade crossing and any nonoperational features of the grade crossing warning system such as total nonoperational character of the system or specific nonoperational features such as the warning lights, crossing gate and/or alarm bell. The transmitted signals are received by an equipped vehicle within range of the transmitter and if decoded, one or more of the related alarm functions within the vehicle are activated. Preferable alarm functions are an audio alarm for each function signal received, as well as optional light (LED) and voice messaging.